Mapbox Google Maps Migration Agent Skill

Mapbox Google Maps Migration Skill

Comprehensive guidance for migrating from Google Maps Platform to Mapbox GL JS. Provides API equivalents, pattern translations, and strategies for successful migration.

Core Philosophy Differences

Google Maps: Imperative & Object-Oriented

• Create objects (Marker, Polygon, etc.)
• Add to map with .setMap(map)
• Update properties with setters
• Heavy reliance on object instances

Mapbox GL JS: Declarative & Data-Driven

• Add data sources
• Define layers (visual representation)
• Style with JSON
• Update data, not object properties

Key Insight: Mapbox treats everything as data + styling, not individual objects.

Map Initialization

Google Maps

const map = new google.maps.Map(document.getElementById('map'), {
  center: { lat: 37.7749, lng: -122.4194 },
  zoom: 12,
  mapTypeId: 'roadmap' // or 'satellite', 'hybrid', 'terrain'
});

Mapbox GL JS

mapboxgl.accessToken = 'YOUR_MAPBOX_TOKEN';
const map = new mapboxgl.Map({
  container: 'map',
  style: 'mapbox://styles/mapbox/streets-v12', // or satellite-v9, outdoors-v12
  center: [-122.4194, 37.7749], // [lng, lat] - note the order!
  zoom: 12
});

Key Differences:

• Coordinate order: Google uses {lat, lng}, Mapbox uses [lng, lat]
• Authentication: Google uses API key in script tag, Mapbox uses access token in code
• Styling: Google uses map types, Mapbox uses full style URLs

API Equivalents Reference

Map Methods

| Google Maps | Mapbox GL JS | Notes |

| ------------------------ | -------------------------------------- | ----------------------------- |

| map.setCenter(latLng) | map.setCenter([lng, lat]) | Coordinate order reversed |

| map.getCenter() | map.getCenter() | Returns LngLat object |

| map.setZoom(zoom) | map.setZoom(zoom) | Same behavior |

| map.getZoom() | map.getZoom() | Same behavior |

| map.panTo(latLng) | map.panTo([lng, lat]) | Animated pan |

| map.fitBounds(bounds) | map.fitBounds([[lng,lat],[lng,lat]]) | Different bound format |

| map.setMapTypeId(type) | map.setStyle(styleUrl) | Completely different approach |

| map.getBounds() | map.getBounds() | Similar |

Map Events

| Google Maps | Mapbox GL JS | Notes |

| ------------------------------------------------- | ---------------------- | --------------------- |

| google.maps.event.addListener(map, 'click', fn) | map.on('click', fn) | Simpler syntax |

| event.latLng | event.lngLat | Event property name |

| 'center_changed' | 'move' / 'moveend' | Different event names |

| 'zoom_changed' | 'zoom' / 'zoomend' | Different event names |

| 'bounds_changed' | 'moveend' | No direct equivalent |

| 'mousemove' | 'mousemove' | Same |

| 'mouseout' | 'mouseleave' | Different name |

Markers and Points

Simple Marker

Google Maps:

const marker = new google.maps.Marker({
  position: { lat: 37.7749, lng: -122.4194 },
  map: map,
  title: 'San Francisco',
  icon: 'custom-icon.png'
});

// Remove marker
marker.setMap(null);

Mapbox GL JS:

// Create marker
const marker = new mapboxgl.Marker()
  .setLngLat([-122.4194, 37.7749])
  .setPopup(new mapboxgl.Popup().setText('San Francisco'))
  .addTo(map);

// Remove marker
marker.remove();

Multiple Markers

Google Maps:

const markers = locations.map(
  (loc) =>
    new google.maps.Marker({
      position: { lat: loc.lat, lng: loc.lng },
      map: map
    })
);

Mapbox GL JS (Equivalent Approach):

// Same object-oriented approach
const markers = locations.map((loc) => new mapboxgl.Marker().setLngLat([loc.lng, loc.lat]).addTo(map));

Mapbox GL JS (Data-Driven Approach - Recommended for 100+ points):

// Add as GeoJSON source + layer (uses WebGL, not DOM)
map.addSource('points', {
  type: 'geojson',
  data: {
    type: 'FeatureCollection',
    features: locations.map((loc) => ({
      type: 'Feature',
      geometry: { type: 'Point', coordinates: [loc.lng, loc.lat] },
      properties: { name: loc.name }
    }))
  }
});

map.addLayer({
  id: 'points-layer',
  type: 'circle', // or 'symbol' for icons
  source: 'points',
  paint: {
    'circle-radius': 8,
    'circle-color': '#ff0000'
  }
});

Performance Advantage: Google Maps renders all markers as DOM elements (even when using the Data Layer), which becomes slow with 500+ markers. Mapbox's circle and symbol layers are rendered by WebGL, making them much faster for large datasets (1,000-10,000+ points). This is a significant advantage when building applications with many points.

Info Windows / Popups

Google Maps

const infowindow = new google.maps.InfoWindow({
  content: '<h3>Title</h3><p>Content</p>'
});

marker.addListener('click', () => {
  infowindow.open(map, marker);
});

Mapbox GL JS

// Option 1: Attach to marker
const marker = new mapboxgl.Marker()
  .setLngLat([-122.4194, 37.7749])
  .setPopup(new mapboxgl.Popup().setHTML('<h3>Title</h3><p>Content</p>'))
  .addTo(map);

// Option 2: On layer click (for data-driven markers)
map.on('click', 'points-layer', (e) => {
  const coordinates = e.features[0].geometry.coordinates.slice();
  const description = e.features[0].properties.description;

  new mapboxgl.Popup().setLngLat(coordinates).setHTML(description).addTo(map);
});

Migration Strategy

Step 1: Audit Current Implementation

Identify all Google Maps features you use:

• [ ] Basic map with markers
• [ ] Info windows/popups
• [ ] Polygons/polylines
• [ ] Geocoding
• [ ] Directions
• [ ] Clustering
• [ ] Custom styling
• [ ] Drawing tools
• [ ] Street View (no Mapbox equivalent)
• [ ] Other advanced features

Step 2: Set Up Mapbox

<!-- Replace Google Maps script -->
<script src="https://api.mapbox.com/mapbox-gl-js/v3.18.1/mapbox-gl.js"></script>
<link href="https://api.mapbox.com/mapbox-gl-js/v3.18.1/mapbox-gl.css" rel="stylesheet" />

Step 3: Convert Core Map

Start with basic map initialization:

• Replace new google.maps.Map() with new mapboxgl.Map()
• Fix coordinate order (lat,lng -> lng,lat)
• Update zoom/center

Step 4: Convert Features One by One

Prioritize by complexity:

• Easy: Map controls, basic markers
• Medium: Popups, polygons, lines
• Complex: Clustering, custom styling, data updates

Step 5: Update Event Handlers

Change event syntax:

• google.maps.event.addListener() -> map.on()
• Update event property names (latLng -> lngLat)

Step 6: Optimize for Mapbox

Take advantage of Mapbox features:

• Convert multiple markers to data-driven layers
• Use clustering (built-in)
• Leverage vector tiles for custom styling
• Use expressions for dynamic styling

Step 7: Test Thoroughly

• Cross-browser testing
• Mobile responsiveness
• Performance with real data volumes
• Touch/gesture interactions

Gotchas and Common Issues

Coordinate Order

// Google Maps
{ lat: 37.7749, lng: -122.4194 }

// Mapbox (REVERSED!)
[-122.4194, 37.7749]

Always double-check coordinate order!

Event Properties

// Google Maps
map.on('click', (e) => {
  console.log(e.latLng.lat(), e.latLng.lng());
});

// Mapbox
map.on('click', (e) => {
  console.log(e.lngLat.lat, e.lngLat.lng);
});

Timing Issues

// Google Maps - immediate
const marker = new google.maps.Marker({ map: map });

// Mapbox - wait for load
map.on('load', () => {
  map.addSource(...);
  map.addLayer(...);
});

Removing Features

// Google Maps
marker.setMap(null);

// Mapbox - must remove both
map.removeLayer('layer-id');
map.removeSource('source-id');

Updating Data Without Flash

Never remove and re-add layers to update data — this reinitializes WebGL resources and causes a visible flash. Instead:

// ✅ Update data in place (no flash)
map.getSource('stores').setData(newGeoJSON);

// ✅ Filter existing data (GPU-side, fastest)
map.setFilter('stores-layer', ['==', ['get', 'category'], 'coffee']);

// ❌ BAD: remove + re-add causes flash
map.removeLayer('stores-layer');
map.removeSource('stores');
map.addSource('stores', { ... });
map.addLayer({ ... });

When NOT to Migrate

Consider staying with Google Maps if:

• Street View is critical - Mapbox doesn't have equivalent
• Tight Google Workspace integration - Places API deeply integrated
• Already heavily optimized - Migration cost > benefits
• Team expertise - Retraining costs too high
• Short-term project - Not worth migration effort

Quick Reference: Side-by-Side Comparison

// GOOGLE MAPS
const map = new google.maps.Map(el, {
  center: { lat: 37.7749, lng: -122.4194 },
  zoom: 12
});

const marker = new google.maps.Marker({
  position: { lat: 37.7749, lng: -122.4194 },
  map: map
});

google.maps.event.addListener(map, 'click', (e) => {
  console.log(e.latLng.lat(), e.latLng.lng());
});

// MAPBOX GL JS
mapboxgl.accessToken = 'YOUR_TOKEN';
const map = new mapboxgl.Map({
  container: el,
  center: [-122.4194, 37.7749], // REVERSED!
  zoom: 12,
  style: 'mapbox://styles/mapbox/streets-v12'
});

const marker = new mapboxgl.Marker()
  .setLngLat([-122.4194, 37.7749]) // REVERSED!
  .addTo(map);

map.on('click', (e) => {
  console.log(e.lngLat.lat, e.lngLat.lng);
});

Remember: lng, lat order in Mapbox!

Additional Resources

• Mapbox GL JS Documentation
• Official Google Maps to Mapbox Migration Guide
• Mapbox Examples
• Style Specification

Integration with Other Skills

Works with:

• mapbox-web-integration-patterns: Framework-specific migration guidance
• mapbox-web-performance-patterns: Optimize after migration
• mapbox-token-security: Secure your Mapbox tokens properly
• mapbox-geospatial-operations: Use Mapbox's geospatial tools effectively
• mapbox-search-patterns: Migrate geocoding/search functionality

Reference Files

The following reference files contain detailed migration guides for specific topics. Load them when working on those areas:

• references/shapes-geocoding.md — Polygons, Polylines, Custom Icons, Geocoding
• references/directions-controls.md — Directions/Routing, Controls
• references/clustering-styling.md — Clustering, Styling/Appearance
• references/data-performance.md — Data Updates, Performance, Common Migration Patterns (Store Locator, Drawing Tools, Heatmaps)
• references/api-services.md — API Services Comparison, Pricing, Plugins, Framework Integration, Testing, Migration Checklist

To load a reference, read the file relative to this skill directory, e.g.:

Load references/shapes-geocoding.md